Method of utilizing die set

ABSTRACT

The method of utilizing a die set in which pins having respective ball bearing cages are employed during the fitting of the dies with conventional posts being substituted therefor during production running of the dies.

United States Patent Inventor Joseph C. Eppich Parma, Ohio Appl. No. 820,475

Filed Apr. 30, I969 Patented Apr. I3, 1971 Assignee Danly Machine Corporation Chicago, Ill.

METHOD OF UTILIZING DIE SET 1 Claim, 5 Drawing Figs.

U.S. Cl 29/465, 76/ I 07 Int. Cl B23q 3/00 Field of Search 29/465; 76/107 [56] References Cited UNITED STATES PATENTS 2,089,795 8/ I 937 Hodge 29/465 2,504,642 4/1950 Burgess 29/465 3, I 26,776 3/1964 Whistler et al... 76/107X 3,386,781 6/1968 Blazek et al. 29/465X 3,504,576 4/1970 Silberman et a1. 29/465X Primary ExaminerCharlie T. Moon Attorney-Wolfe, Hubbard, Leydig, Voit & Osann ABSTRACT: The method of utilizing a die set in which pins having respective ball bearing cages are employed during the fitting of the dies with conventional posts being substituted therefor during production running of the dies.

Patented A ril 13, 1971 2 Sheets-Sheet 1 W M w 2 WM W% Patented April 13, 1971 3,514,922

2 Shoots-Sheet 2 METHOD OF UTILIZING DIE SET It is an object of the invention to provide a method of utilizing a die set to permit easy repeated separation and engagement of the die set required incident to fitting of the dies while achieving the advantages of maximum strength and rigidity during the operation of the dies under running conditions. It is thus an object to achieve, in a single die set, the mutually exclusive features and advantages normally obtainable by the use of completely separate die sets. More specifically, it is an object of the invention to provide a method of utilizing a die set which greatly facilitates the fitting of a pair of dies and which conserves time and effort on the part of the diemaker but which nevertheless provides the strength and rigidity which is characteristic of conventional posts and bushings. It is a general object to provide a procedure for utilizing a die set which achieves a high degree of convenience and economy.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIG. 1 is a die set having a punch and die mounted therein and with conventional posts and bushings in place;

FIG. 2 is a fragmentary section, in elevation, looking along the line 2-2 in FIG. 1;

FIG. 3 shows the die set of FIG. 1, but with pins and ball bearing cages substituted for the posts;

FIG. 4 is a fragmentary section, in elevation, looking along the line 4-4 in FIG. 3; and

FIG. 5 is a view similar to FIG. 4 but showing the pin and ball bearing cage inserted in the bushing.

Turning now to the drawings, there is shown in FIG. I, a die set having a lower portion 11 and an upper portion 12 intended for mounting on the bolster and slide, respectively, of a power press. Secured to the lower portion 11 of the set is a die 16 which cooperates with an upper die, here in the form of a punch 17, secured to the upper portion 12. The members l6, 17 may be fastened firmly in registering position by any suitable means, as for example machine screws 18 of which the heads are shown in FIG. 1.

For the purpose of maintaining the portions of the die set,

. and the dies, in exact alignment and register as the die set is engaged and separated during the running of the press, the lower portion 11 is fitted with a pair of posts while the upper portion 12 is fitted with cooperating bushings.

Thus as shown in FIGS. I and 2, the lower portion II has a post 20 having a base portion 21 which is snugly fitted in a socket 22 to a depth limited by bottoming engagement of an integral flange 23. The post is clamped in position by means of clamping lugs 24 which engage the flange and which are secured by machine screws 25 screwed into tapped holes in the member 11.

For telescoped engagement with the post, a bushing is provided in the upper portion 12 of the die set having a base 31 which is received in a socket 32. An integral flange 33 provides firm bottoming, and the bushing is clamped in place by means of lugs 34 having associated clamping screws 35. Corresponding reference numerals are employed to indicate corresponding parts of the second post and bushing.

In accordance with the present invention, the posts 20 are replaced by relatively narrow pins having bases which are dimensioned to fit in the sockets and having ball bearing cages slidable thereon which are dimensioned to fit snugly in the cooperating bushings, thereby to keep the upper and lower dies in a precise condition of register and alignment during the fitting of the dies and with the pins and ball bearing cages being removed and replaced by the posts, without disturbing the dies, to provide maximum strength and rigidity for making a production run. Thus turning to FIGS. 3 and 4, pins, having associated ball bearing cages are substituted for the posts shown in FIG. I and 2. Taking the pin shown in FIG. 4 and which has been indicated at 40, by way of example, it includes a base portion 41 which is dimensioned to fit snugly in the socket 22 to a depth limited by an integral flange 43. The pin is held seated by the lugs 24 and machine screws 25. Slidable on the pin is a ball bearing cage 50 having a two-dimensional pattern of balls 51 and which is upwardly pressed by a coil spring 52. For the purpose of positioning the cage in proper phase position when the upper and lower portions of the die set are completely separated, a washer 53 is provided held in place by a screw 54 and having radially projecting tangs which slide in grooves 55 which are milled in diametric positions within the cage.

The outer diameter of the cage, i.e., the locus of the extremities of the balls when the balls are in contact with the pin 40, is so chosen as to provide a snug fit with respect to the inner surface of the bushing 30; indeed, the diameter of the outer extremities of the balls may very slightly exceed the inner diameter of the bushing 30 to provide a slight degree of preload thereby to insure a snug fit.

With the pins 40 installed and clamped in position by the clamping lugs 24 and with the ball bearing cage 50 mounted thereon, the two portions of the die set are brought together as shown in FIG. 5 with telescoping of the pin and cage into the bushing. Because of the use of the pattern of antifriction balls, the two portions of the die set may thereafter be easily engaged and separated by the diemaker with only light force as required at the bench during the fitting of the dies.

After the dies have been formed to a perfect fit, and without disturbing the positions of the dies with respect to the die set, the clamping lugs 24 are released, the pins 40, with their ball cages and springs are removed, and the posts 20 are substituted and seated firmly in position by the tightening of the clamping lugs. Since the pins and posts are concentric, this substitution does not affect the relative lateral positions of the dies 16, 17 with respect to one another, and a high order of positional accuracy is preserved between them. Substitution of the relatively massive posts 20 ensures that maximum strength and rigidity will be effective to preserve the relative positions of the dies notwithstanding the forces which are imposed during production running. The added friction which is characteristic of the use of conventional posts is of no account when the die set is being operated on a production basis.

Thus it will be seen that the pins and ball bearing cages are utilized only during the die-fitting stage and are idle when the die set is being actually used for production. In a shop in which a number of die sets are in constant use, a set of pins and ball bearing cages may be kept for use exclusively for fitting purposes, provided that there is standardization of the posts and bushings. Where it is desired to secure the benefits of the present invention with a single die set, the die set, when purchased, may be supplied with standard posts and bushings and with a pair of pins and ball cages as an auxiliary for diefitting purposes only. In either event, the substitution procedure discussed herein enables two sets of mutually exclusive features and advantages to be simultaneously obtained in the same basic structure. That is, the pins and cages may be used during the fitting cycle to obtain maximum freedom of movement, thereby to reduce the time and effort required by the diemaker, and the regular posts employed under running conditions when maximum strength and rigidity are required and when freedom of movement is of no consequence.

The above procedure permits the attaining of a high degree of economy inasmuch as it is no longer necessary to have complete die set assemblies of both the antifriction and standard type as required in the past.

I claim:

1. The method of utilizing a die set in the fitting and running of a pair of dies secured to the upper and lower portions of the set, the die set having cooperating posts and bushings, at least the posts being demountable in respective sockets and having means for clamping them in position, which comprises mounting in said sockets pins having bases dimensioned to fit in the sockets and having ball bearing cages respectively slidable thereon dimensioned to fit snugly in said bushings, securing said clamping means to maintain the pins seated in the sockets, repeatedly engaging and separating the die set incident to fitting the dies, removing the pins and cages while maintaining the dies in position, installing the posts in the sockets, securing said clamping means to maintain the posts seated in the sockets, and thereafter repeatedly engaging and separating the die set incident to production running of the dies. 

1. The method of utilizing a die set in the fitting and running of a pair of dies secured to the upper and lower portions of the set, the die set having cooperating posts and bushings, at least the posts being demountable in respective sockets and having means for clamping them in position, which comprises mounting in said sockets pins having bases dimensioned to fit in the sockets and having ball bearing cages respectively slidable thereon dimensioned to fit snugly in said bushings, securing said clamping means to maintain the pins seated in the sockets, repeatedly engaging and separating the die set incident to fitting the dies, removing the pins and cages while maintaining the dies in position, installing the posts in the sockets, securing said clamping means to maintain the posts seated in the sockets, and thereafter repeatedly engaging and separating the die set incident to production running of the dies. 